1. Field of the Invention
The present invention relates to a multilayer wiring board and a method of making the same.
2. Related Art
JP-A-2003-347738 discloses a multilayer wiring board in which an insulating layer formed of a liquid crystal polymer while having a conductive composition filled in a via hole formed in a predetermined region and a conductor layer formed of a patterned conductive material are alternately laminated, wherein the number of the conductive composition coaxially formed in a laminate direction between the insulating layer and the conductor layer is limited and the conductive composition over this lamination is formed at a position not overlapping with the one formed coaxially.
According to the multilayer wiring board disclosed by JP-A-2003-347738, when laminating the insulating layer and the conductor layer, if the coaxially formed conductive composition is over a predetermined limited number and if the conductive composition is further formed, it is formed at a position not overlapping with the one already formed coaxially. Therefore, even when the pressure is applied on the laminated insulating layer and the conductor layer, it is possible to ensure the reliability of interlayer connection since it is possible to prevent the application of excessive pressure to the coaxially disposed conductive composition.
Furthermore, JP-A-2000-208946 discloses a multilayer wiring board comprising an insulating layer, a wiring board preliminarily having wiring patterns on both sides of an interlayer insulating layer formed of a liquid crystal polymer and provided on the insulating layer, and an interlayer connection part penetrating in a thickness direction of the insulating layer and connecting between the wiring patterns of the wiring board.
According to the multilayer wiring board disclosed by JP-A-2000-208946, since the insulating layer and the wiring board are jointed and integrated without using an adhesive agent but using a liquid crystal polymer, it is possible to clear the environmental problem caused by an existence of adhesive agent containing a flame retardant.
However, in the multilayer wiring board according to JP-A-2003-347738, plural insulating layers are formed of the same liquid crystal polymer, it takes thus long time for a heat treatment process to adhere by laminating one insulating layer and another insulating layer. Furthermore, in the multilayer wiring board according to JP-A-2000-208946, since the wiring board and the insulating layer are integrated in the state that a wiring pattern is preliminarily formed on the wiring board, the bond strength in the region where the wiring pattern is preliminarily formed may not be enough.